1. Field of the Invention
The present invention relates generally to wire and cable connectors and, more particularly, to electrical connectors for communication circuits that compensate for cross-talk along different signal paths within the connector.
2. Description of the Related Art
Connectors for communication wires and cables are normally used to connect the ends of pairs of wires which define discrete signal paths. A typical industry type of communication connector is the RJ-45 communication connector. This connector contains eight wires to provide four pairs of terminal wires where each pair of wires defines a single signal path. Within the typical RJ-45 connector, the eight wires which make up the four pairs of conductors are closely spaced and normally follow paths which are parallel to each other for the length of the connector body. This close positioning of the wires strongly suggests that cross-talk may be induced between and among different pairs of wires within the RJ-45 connector. As broadly defined herein, cross-talk occurs when signals conducted over a first signal path, e.g., a pair of terminal contact wires within a connector, are partly transferred by inductive or capacitive coupling into a second, adjacent signal path (e.g., another pair of terminal contact wires) within the connector. The transferred signals are delineated as xe2x80x9ccross-talkxe2x80x9d in the second signal path, and they act to degrade other signals that are being routed through the second path.
Applicable industry standards for rating the extent to which communication connectors exhibit cross-talk do so in terms of so-called near end cross-talk (NEXT). Such ratings are typically specified for a mated pair of connectors, e.g., a type RJ-45 plug and jack combination, where the input terminals of the plug connector are used as a reference plane.
U.S. Pat. No. 5,186,647, which is assigned to the assignee of the present invention, discloses an electrical connector for conducting high frequency signals. The connector has a pair of metallic lead frames mounted flush with a dielectric spring block, with connector terminals formed at opposite ends of the lead frames. The lead frames themselves include flat elongated conductors, each of which includes a spring terminal contact wire having a free end supported in cantilever fashion for contacting a corresponding terminal wire of a mating connector, and an insulation displacing connector terminal at the other end for connection with an outside insulated wire lead. The lead frames are placed over one another on the spring block, and three conductors of one lead frame have cross-over sections configured to overlap corresponding cross-over sections formed on three conductors of the other lead frame.
It is also known to provide cross-talk compensating circuitry on or within layers of a printed wire board to which spring terminal contact wires of a communication jack (also supported in cantilevered fashion) are connected within the jack housing. See U.S. Pat. Nos. 5,997,358 and 6,176,741.
Communication links using unshielded twisted pairs of copper wire are now expected to reliably support data rates up to not only 100 MHz, i.e., industry standard xe2x80x9cCategory 5xe2x80x9d performance, but up to as much as 250 MHz or proposed xe2x80x9cCategory 6xe2x80x9d performance levels.
The use of spring terminal contact wires supported in a cantilevered fashion can contribute to circuit discontinuity caused by bent contacts, that are not aligned, or that make high impedance physical contact. The use of cross-over conductors that follow irregular paths in a connector are expensive to manufacture and assemble.
Accordingly, there is a clear need for a communications connector that has cross-talk characteristics that approach Category 6 levels, that does not require complex cross-over sections, that is adaptable for connection to cross-talk compensation circuitry on or within layers of a printed wire board to which spring terminal contact wires of a communication jack are connected within the jack housing, that avoids the use of spring terminal contact wires having a free end supported in cantilevered fashion, and that is simple in design and economical to produce.
In accordance with the invention, there is provided a telecommunication jack that is free of cross-over sections, has cross-talk characteristics that approach Category 6 levels, and avoids the use of spring contact wires supported in a cantilevered fashion. This is achieved in a preferred implementation by spring terminal contact wires that are arch shaped. Each spring wire has a first leg having an end, a second leg having an end and an apex portion located between the first and second legs where the ends of the legs are supported on a wire board and each end makes electrical contact with separate conductive pads. When utilized in an operating circuit, one end and leg of a spring terminal contact wire is coupled to a conductive pad on the wire board that is in a current carrying signal path, and the other end and leg of that spring terminal contact wire is coupled to a different conductive pad on the wire board adapted for connection to a cross-talk compensating component. In accordance with the invention, both pads of the wire board are connected to a common spring terminal contact wire, although only one pad and one leg of the arch shaped spring wire is in the current carrying signal path; the pad and leg connected to the cross-talk compensating component is not in the current carrying signal path. The legs of the arch shaped spring terminal contact wires can be of equal or unequal length, the arch can be semi-circular, triangular or the like, and the conductive pads on the wire board of adjacent spring wire terminals can be either aligned or staggered in distance from the edge of the wire board.
Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims. It should be further understood that the drawings are not necessarily drawn to scale and that, unless otherwise indicated, they are merely intended to conceptually illustrate the structures and procedures described herein.